Simon U.S. Pat. Nos. 4,221,909 and 4,221,911 and Giner-Sorolla U.S. Pat. No. 4,221,910 and Faanes International Journal of Immunopharmacology, Vol. 2, No. 3, page 197 (1980), Florentine, International Journal of Immunopharmacology, Vol. 2, No. 3, page 240 (1980), Hadden, International Journal of Immunopharmacology, Vol. 2, No. 3, page 198 (1980), Pahwa, International Journal of Immunopharmacology, Vol. 2, No. 3, page 199 (1980), Wybran, International Journal of Immunopharmacology, Vol. 2, No. 3, page 201 (1980) and Simon, 4th International Congress of Immunology, Paris (1980) show that erythro-9-(2-hydroxy-3-nonyl)-hypoxanthine (NPT 15392), as well as other members of the series described in the patents cited above are potent immunomodulating agents which have been demonstrated to enhance depressed immunity in both animals possessing tumors, Sato, International Journal of Immunopharmacology, Vol. 2, No. 3, page 200 (1980), as well as in humans with various tumors, Simon, American Chemical Society Book of Abstracts, 182nd American Chemical Society Meeting (1981). While the synthesis of these therapeutically useful agents can be carried out by the methods described in the patents cited above, their production, e.g. the production of NPT 15392, on a large scale using those methods was cumbersome, costly, and time consuming. The entire disclosure of the three U.S. patents are hereby incorporated by reference and relied upon.